Document: U99_001
page 12 of 24
5.4 Pipe works
5.4.1
General
The pipe work must be absorbed directly in front of the pump, must be assembled stress less to the pump and possible
charges on connections must be absorbed by suitable measures (e. g. with compensators,…) Pay attention to heavy
forces, which may arise at thermal expansion and at filling up big tubes.
Pipeworks must be designed as short and straight
as possible in order to avoid friction losses. Make sure, that contamination of pump is avoided. Pipes must be laid in a way
that air cushions during filling-up are avoided. Make sure that no flange gaskets project in pipes which reduce the cross
section of pipes.
The pipework must be built in a way that enables dismantling of pump without draining of vessel or pipes.
To get correct data at site, the pressure measurements shall be acc. to velocity mentioned in point
5.4.2 Dimensioning of piping
. Elbows, valves, taper pieces etc. could after the pressure measurement points.
Therefore these parts should not ot close at the pressure measurement points. Test on circulation pumps are carried out
according to DIN EN ISO 9906:2023-3. The arrangement for the flow measure system should be according to the
instructions of the supplier. Consider
9.3 Tightening torques
5.4.2
Dimensioning of piping
In order to minimize losses due to friction in pipes, the flow velocity in the suction, respectively feed pipe must not exceed
1.5 m/s and 2.5 m/s in pressure lines.
Suction pipe
It need to be assured that the pump will be operated always with inlet-pressure on the suction side.
The inlet pressure in addition to the maximum differental pressure of the pump shall not exeed the maximum
allowable pressure of the pump.
Minimum liquid level
The construction of the conduits and the liquid supplies are to be designed in accordance with the rules of the
conduit manufacturers in such a way that the pump can not suck in any air.
A dry-run may cause considerable damage to the pump and the seal.